Unusual phenomenon

[tonigau]

This is probably more of a physics topic ?
I received a gift of a nice old forklift battery charger, It got wet outside in the rain.
I observed the ammeter needle move when I touched the front , played around a bit & got inconsistent but repeatable needle movement & it would even hold a position, (doesnt seem like sticky pivot) .
There would be high humidity inside the meter as there is h2o condensate visible inside the meter front.
___ Strange.
After dry out it no longer reacts to touch.

Video attached

 

[rjenkinsgb]

Very strange!
I'd guess it's some kind of electrostatic induction effect? Although it's damp, the plastic is still a good insulator as water is beading on it, not forming a continuous film.

Electrostatic induction - Wikipedia

en.wikipedia.org

 

[JimB]

I have seen this effect before, on several meters, each completely different form each other.

I believe that the effect is due to electrostatic charging of the meter "window".

JimB

 

[augustinetez]

Seconded - electrostatic influence - very common.

 

[Pommie]

Most BIG discoveries start with the phrase, that's weird!

Mike.

 

[unclejed613]

yes, electrostatic induction. the plastic (or on older meters, glass) acts as a dielectric, which charges up if you touch it with a static charge on your finger the charge inside acts on the needle and makes it move.

 

[For The Popcorn]

I had a grand old-shool volt meter (maybe ammeter?) but the glass was cracked. No problem I thought, and laser-cut an acrylic lens to replace the cracked glass one. A total bust. The electrostatic charge wouldn't even let the needle move.

 

[Nigel Goodwin]

I had a grand old-shool volt meter (maybe ammeter?) but the glass was cracked. No problem I thought, and laser-cut an acrylic lens to replace the cracked glass one. A total bust. The electrostatic charge wouldn't even let the needle move.

Yet most meters, including the one at the start of this thread, have plastic 'glass'.

 

[For The Popcorn]

In my case, the meter is 70+ years old. Glass lenses were the norm.

The lens I cut was plain old acrylic. I don't know what plastic is used in meters; perhaps it has antistatic properties. At any rate, I was just relating my failed attempt at creating a replacement lens.

 

[tonigau]

The electrostatic charge wouldn't even let the needle move.

You could try using an anti-static cleaner on both sides of the acrylic & don't wipe dry. This would reduce the surface resistivity.

 

[atferrari]

Brushing my Kamoden HT-100B (bought it 45 ++ years ago), got this. Just by touching it with the palm of the other hand, it went to zero. A dry day here.

 

[Nigel Goodwin]

Brushing my Kamoden HT-100B (bought it 45 ++ years ago), got this. Just by touching it with the palm of the other hand, it went to zero. A dry day here.

You get dry days?

 

[atferrari]

You get dry days?

No idea what your question tries to express.

 

[Nigel Goodwin]

No idea what your question tries to express.

Simply how often it seems to rain in the UK

 

[Pommie]

Simply how often it seems to rain in the UK

Allegedly, why so many games programmers came from the north of England. Too wet to do anything else.

Mike.

 

[Nigel Goodwin]

Allegedly, why so many games programmers came from the north of England. Too wet to do anything else.

Mike.

He, he

 

[atferrari]

Not in my place where high humidity is frequent, but in the flat part of Patagonia dry weather is quite common. I like that.

You suffer much less summer or winter.

The most impressive fog I encountered ashore was with our vessel alongside at Liverpool.

 

[Pommie]

Don't understand most of your questions but
Now I live in Australia, I love rain. It was horrid and cold in the UK but now warm and nice.
We occasionally get low cloud (fog) but it tends to dissipate by about 8am.
The size Australia is, we get all types of weather.
Top part tropics, below just awesome.

Mike.

 

[atferrari]

Don't understand most of your questions but
Now I live in Australia, I love rain. It was horrid and cold in the UK but now warm and nice.
We occasionally get low cloud (fog) but it tends to dissipate by about 8am.
The size Australia is, we get all types of weather.
Top part tropics, below just awesome.

Mike.

Is the above addressed to me, Mike?
Questions? I posed only one and Nigel answered already.

 

[Dick Cappels]

I can touch the plastic face of my meter all I want and it never affects the reading.